Alright, let's work through 81039120 times 36661488 step by step
81039120 × 36661488 = 36661488 × (81039120)
+ 36661488 × 0 what gives us 0
+ 36661488 × 20 producing 733229760
+ 36661488 × 100 yielding 3666148800
+ 36661488 × 9000 that results in 329953392000
+ 36661488 × 30000 giving us 1099844640000
+ 36661488 × 000000 resulting in 0
+ 36661488 × 1000000 yielding 36661488000000
+ 36661488 × 80000000 which equals 2932919040000000

= 2971014725410560
